What is the use of Work Bench in Salesforce?

Workbench is a web-based tool which helps administrators and developers to interact with Salesforce for Data Insert, Update, Upsert, Delete and Export. It also supports the Undelete Program, Deploy, Retrieve, Rest Explorer and Apex Execute actions too. Workbench is an advanced tool that is built using JavaScript and PHP, where it supports more than 5 million records for Data manipulation!
For any Data Manipulations in Salesforce, we have Data Loader. To update one or two records using Data loader, we HAVE to export .CSV file, modify the excel file and then load it. But in case of Workbench, we can update a single record; we only require the 15 digit UniqueId of the record and update the fields as required. This is one of the best functionality of Workbench when compared to Data loader.
Uses:
In the browser, it is easy to read a table because of the simplified result information.
It is easy to build a SOQl query quickly.
It is easy to build SOSL function.
Using Workbench, the Purge option permanently deletes items from the recycle bin; Use 15 digit unique ID
It is User friendly, Simple to use which saves your settings through the session.
As Workbench is neither Supported, nor a Product of Salesforce, hence no support is provided by Salesforce. For any kind of support or issues we need to look for Open source communities.